Your ideal weight is the one you feel happiest at concommitent with remaining healthy and functional in your desired activities.
I have to assume that your goal doesn't involve "showing off your curves this summer". Excessive short-term weight loss, especially chemically driven, is not healthy.
Get down to the gym and work hard there, do plenty of general activity, even if that's just walking an hour a day, and, if your diet is even vaguely reasonable and you are not already at very low BF, the weight will melt away while you grow and tone your muscle. There's a forum on here dedicated to diet and you'll get lots of good help there.